Why does this ggplot2 graph fail to plot when looped over?

Question

I'm trying to plot a large number of graphs by looping over some data, but graphs produced when the plotting functions are encapsulated within a for loop are corrupted PDFs.

I've reduced it down to a minimal example here; this should produce 1.pdf as expected, but 2.pdf and 3.pdf generated inside the loop are slightly smaller files, and don't open in PDF reader software.

i <- 1

pdf(paste(i,'.pdf',sep=''))
ggplot(NULL,aes(x=i, y=i)) +
  geom_point() +
  coord_cartesian(xlim = c(0, 10), ylim = c(0, 10)) +
  ggtitle(paste('i =', i))
dev.off()


for(i in 2:3) {
  pdf(paste(i,'.pdf',sep=''))
  ggplot(NULL,aes(x=i, y=i)) +
    geom_point() +
    coord_cartesian(xlim = c(0, 10), ylim = c(0, 10)) +
    ggtitle(paste('i =', i))
  dev.off()
}

What's wrong?

score 2 · Accepted Answer · answered Jul 23 '13 at 12:20

2

You have to print it: print(ggplot(...))

answered Jul 23 '13 at 12:20

shadow

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I think that's right (silly mistake!), but why then does it work outside the loop? – Andrew Steele Jul 23 '13 at 12:23
1

FAQ 7.22 http://www.hep.by/gnu/r-patched/r-faq/R-FAQ_73.html – baptiste Jul 23 '13 at 12:27

Why does this ggplot2 graph fail to plot when looped over?

1 Answers1